Experience in Saskatchewan and elsewhere has shown that the International Classification of Diseases coding is inadequate for the comprehensive recording of signs and symptoms that are essential for identifying potential adverse drug reactions such as cough associated with angiotensin-converting enzyme inhibitors. Thus, either a new coding system has to be developed by the monitoring organization, as was done in prescription-event monitoring , raising issues of noncomparability with other methods, or an existing one used, such as the World Health Organization’s Adverse Reaction Terminology, the Council for International Organizations of Medical Sciences’ system, the United States Food and Drug Administration’s Coding Symbols for Thesaurus of Adverse Reaction Terms or, more comprehensively, the Committee on Safety of Medicines’ Medical Dictionary for Regulatory Activities. buy prednisone
Considerable effort would have to be focused on how effectiveness is measured because information recorded in the health care system tends to be centred on the recording of symptoms and diseases, rather than on the benefits or effectiveness of the therapy. Effectiveness of treatment is more than the absence of symptoms.
What should be measured? Efficacy is the extent to which a drug “produces a beneficial result under ideal conditions” , while effectiveness is the extent to which a drug, “when deployed in the field, does what it is intended to do for a defined population” , ie, how well it works when used in normal medical practice. Efficacy is demonstrated by premarketing clinical trial data, whereas effectiveness is shown using real-world experiential data . Generally, the effectiveness of a drug used in the outpatient setting is considerably lower than its efficacy. A drug that is highly efficacious when taken by patients satisfying precise selection criteria is inevitably less effective in everyday use where patients excluded from the clinical trials due to their demographic or disease characteristics receive the drug, compliance is unmonitored and the prescribing of the drug may be inappropriate.